# Bugs Fixed* InnoDB Storage Engine: The “random read-ahead” feature that was removed from the InnoDB Plugin is now available again. Because it is only helpful for certain workloads, it is turned off by default. To turn it on, enable the innodb_random_read_ahead configuration option. Because this feature can improve performance in some cases and reduce performance in others, before relying on this setting, benchmark both with and without the setting enabled. * Partitioning: Auto-increment columns of partitioned tables were checked even when they were not being written to. In debug builds, this could lead to a server crash. * The option-parsing code for empty strings leaked memory. * Replication: Processing of corrupted table map events could cause the server to crash. This was especially likely if the events mapped different tables to the same identifier, such as could happen due to Bug#56226. Now, before applying a table map event, the server checks whether the table has already been mapped with different settings, and if so, an error is raised and the slave SQL thread stops. If it has been mapped with the same settings, or if the table is set to be ignored by filtering rules, there is no change in behavior: the event is skipped and IDs are not checked. * ALTER TABLE {MODIFY|CHANGE} ... FIRST did nothing except rename columns if the old and new versions of the table had exactly the same structure with respect to column data types. As a result, the mapping of column name to column data was incorrect. The same thing happened for ALTER TABLE DROP COLUMN ... ADD COLUMN statements intended to produce a new version of the table with exactly the same structure as the old version. * For a lower_case_table_names value of 1 or 2 and a database having a mixed-case name, calling a stored function using a fully qualified name including the database name failed. * Previously, Performance Schema table columns that held byte counts were BIGINT UNSIGNED. These were changed to BIGINT (signed). This makes it easier to perform calculations that compute differences between columns. * For MyISAM tables, attempts to insert incorrect data into an indexed GEOMETRY column could result in table corruption. * A race condition between loading a stored routine using the name qualified by the database name and dropping that database resulted in a spurious error message: The table mysql.proc is missing, corrupt, or contains bad data * Upgrades using an RPM package recreated the test database, which is undesirable when the DBA had removed it.